Landcover data consisted of a 2005 classified landcover map of North America developed by the Commission for Environmental Cooperation. We used 15 of the 19 landcover classifications (see below); the other four classes described dry and subtropical habitats not present in the study region. Landcover was mapped at a 250-m resolution, so there were or 256 land cover pixels per 4-km model cell. For model-building purposes, we summarised landcover proportions according to the distribution of survey locations within the 4-km grid cell: the landcover type for each survey location within a cell was determined by the point-count center. For prediction, we used the proportions of all landcover types within each cell.
Landcover classes (15) used in Maxent modelling